Implement retainer



Jan. 27, 1942. R. o. ALLEN 2,270,840

IMPLEMENT RETAINER Filed Jan. 26, 1959 INVENTOR HlS ATTORNEY Patented Jan. 27, 1942 IMPLEMENT RETAINER Roy 0. Mien, Athens, Pa., assignor to Ingersoll- Rand Company, Jersey City, N. L, a corporation of New Jersey Application January 26, 1939, Serial No. 252,9

3 Claims.

This invention relates to pneumatic tools, and more particularly to implement retainers for tools of the hammer type in which the working implement extends into the end of the ool casing part pointed out hereinafter.

In the drawingaccompanying this specification and in which similar reference numerals refer to similar parts:

Figure 1 is an elevation, partly in'section, of the front end of a pneumatic tool equipped with an implement retainer constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 2--2, and

Figure 3 is a side view, partly broken away, of the front end of the percussive tool taken through Figure 1 on the line 3-3 and showing the retainer elements.

Referring more particularly to the drawing, designates the front end of a pneumatic tool casing and 2| a working implement extending into a bore 22 in the casing 20 to receive the blows of a hammer piston 23.

The hammer piston is reciprocable in a bushing 24, the front end 25 of which serves as an abutcasing 20 and is located near the front end thereof. The forward end of the slot 21 serves as a seating surface 28' upon which the pawl 26 is tiltably seated and is rounded as is also the cooperating end 23 of the pawl.

The surface 28 is inclined somewhat with re spect to the axis of the working implement 2| so that the pawl 26 will, in its retaining position, incline towards the working implement but is prevented from actual contact with the implement 21 by a-surface 30 extending longitudinally of the Cal casing normal to the surface 23 and forming the bottom of the slot 121. ,The surface 30 is, therefore, also inclined with respect to the bore 22 and, in the form of the invention shown, merges into the surface of the bore at a point intermediate the ends of the slot 21. Owing to this arrangement an opening 31 is defined between the upper portion of the slot and the bore 22 to permit the implement abutting portion 32 of the pawl 23 to project into the bore 22 and into a slot 33 extending lengthwise of the adjacent portion of th'e working implement.

On the implement abutting portion 32 is a surface 34 lying in parallelism with the adjacent surface of the slot 33, and on the top of the portion 32 is a seating-surface 35 which is inclined with respect to the surface 34 at substantially the same degree of inclination as a shoulder 33 at the upper end of the slot 33 wherewith it cooperates to prevent the working implement 2| from sliding out of the bore 22. A beveled surface l3 at the rear end of the working implement and on the same side as the slot 33 serves as a cam to tilt the pawl out of the retaining position during the insertion of the implement 2| into the bore 22.

In order to normally maintain the pawl 26 in position to prevent accidental removal of the working implement from the casing, said pawl is constantly urged against the surface 30 by a spring 31 seated with one end into a socket 33 in the upper end of the pawl. The opposite end of the spring seats against the inner surface of a spring clip 39 arranged in an annular groove 40 in the periphery of the casing 20. The spring clip 39 thus overlies the slot 21 to fully enclose the retaining element and thereby prevent the entrance of foreign matter into the slot.

To the end that the pneumatic tool may present a smooth exterior surface so that the casing may be conveniently gripped adjacent its front end the groove 40 is of such depth that the external surface of the clip ring 33 lies flush with the surface of the casing. A pin 4| seated in the casing 20 extends into the slot in the spring clip and engages the end surfaces 42 defining said slot to keep the spring clip from rotating into a position in which its slot may be placed in communication with the slot 21.

In practice, the pawl 26 is constantly urged toward the working implement by the spring 31 so that the implement abutting portion 32 will extend into the bore 22, and when the working implement is inserted into the bore 22 the inclined surface 19 will engage the portion 32 of the tool and rock the pawl out of retaining position.

After the shoulder 36 passes over the portion32 the spring 31 will rock the pawl 26 into the retaining position in which the-portion 32 lies in 1 the casing arranged radially of the bore extending from the outer casing surface to the bore and having continuous parallel side walls longitudinally of the casing, a seating wall at the forward end of the slot, a free retainer in the slot lying between the parallel side walls wholly within the outer casing surface and tiltably seated with one end upon the seating wall and the other end extending into the bore, and a wall in the slot engaging the parallel side walls and the seating wall to limit the distance that the retainer may extend into the bore.

2. An implement retainer for percussive tools, comprising a casing having a bore, a slot through the casing arranged radially of the bore extending from the outer casing surface to the bore and having continuous parallel side walls longitudinally of the casing, an inclined surface engaging the parallel side walls and extending longitudinally of the slot, a free retainer in the slot lying between the parallel side walls extending into the bore and having an inclined surface to engage the first mentioned inclined surface for limiting the distance that the retainer may extend into the bore, a spring to hold the retainer in retaining position, and a second spring encircling the casing forming a closure for the slot and a seat for the first said spring.

3. An implement retainer for percussive tools, comprising a casing having a bore, a slot through the casing arranged radially of the bore extending from the outer casing surface to the bore and having continuous parallel side walls longitudinally of the casing, a seating surface engaging the parallel side walls at the forward end of the slot, an inclined surface engaging the parallel side walls extending from the seating surface longitudinally of the slot, a pawl lying between the parallel side walls tiltably seated with one end upon the seating surface extending into the bore and having an inclined surface to engage the first mentioned inclined surface for limiting the distance which the pawl may extend into the bore, a socket in the pawl, a spring in the socket to hold the pawl in retaining position, and a spring ring encircling the casing forming a closure for the slot and a seat for the spring.

ROY O. ALLEN. 

